2-(1-Hydroxyethyl)-5-hydroxynaphtho[2,3-b]furan-4,9-dione of the following formula:
is an optically-active compound contained in Bignoniaceae, Taheebo (Tabebuia avellanedae Lorentz ex Griseb), which is β-isomer and is known to have an excellent anticancer activity (see, for example, Patent Document 1). However, a method for obtaining 2-(1-hydroxyethyl)-5-hydroxynaphtho[2,3-b]furan-4,9-dione is unknown except extraction from the said plant, and hence, 2-(1-hydroxyethyl)-5-hydroxynaphtho[2,3-b]furan-4,9-dione has not sufficiently been used as a medicine due to the rare availability of the plant and very low (0.05%) yields therefrom (see, for example, Nonpatent Document 1).
[Patent Document 1] JP2669762
[Nonpatent Document 1] Shinichi Ueda et al., Phytochemistry, 1994, Vol. 36(2), p. 323-325